Hydrofining with sulfate regenerated catalyst



Feb. 26, 1952 M. H. GWYNN 2,587,149

HYDROFINING WITH SULFATE REGENERATED CATALYST Filed Feb. 10, 1948 I5 Sheets-Sheet l HYDROFINING LIQUID FEED l4 Q'iv I i 6 SPENT 24 i 55 POWDER 1 HOPPER I HYDE PRODUCT 56 V\ 40 MfiKE-UP HYDROGEN 59 FURNHC STEHM 2 s'rRIPPER INVENTOR M. H. GWYNN s Sheets-Sheet 3 Filed Feb. 10, 1948 ZOFrDJOW oo mz m3 mm;

.IIL

INVENTCR Patented Feb. 26, T952 HYDROFININ G WITH SULFATE REGENERATED CATALYST Marion H. Gwynn, Mountain Lakes, N. J. Application February 10, 1948, Serial No. 7,45 6

12 Claims.

This invention comprises the ,hydrofining of cruder and more volatile organic vapors, preferably hydrocarbon vapors, with a fluidized sulphur sensitive catalytic powder under gradient conditions, together with novel means for reactivating the powder. Thus a crude sulphur bearing motor fuel distillate is contacted with a fluidized nickel or similar catalyst at a gradient of non-pyrolytic temperatures, preferably obtained by means comprising cooling additions of gaseous hydrogen, to substantially desulphurize and refine said distillate, then reactivating the powder by converting the highly sulphided nickel to nickel sulphate solution, precipitating said nickel as a readily reducible oxygenated compound by adding an aqueous solution of a highly alkaline compound of sodium, preferably sodium carbonate, then separating, drying and converting said precipitated nickel compound to an homologous sized reactive powder and reusing said powder in the last or coolest hydrofining stage.

An objector my invention is to provide an economical and maximum yield hydrofining method for producing a high quality motor fuel or naphtha from high sulphur cracked distillate withoutysubstantial loss other than sulphur. Becauseof the relatively low hydrofining temperatures, essentially no chemical losses other than desulphurization are encountered. Thus my hydrofining can be the final chemical step in the eflicient refining of low grade crude petroleum. A hydrofined motor fuel distillate requiring no further distillation may be produced by selecting a crude distillate whose boiling range is slightly higher than that desired for the finished motor fuel.

Another object of the invention is to produce a product of improved saturation. Thus the catalytic surface reacts with sulphur from the organic vapor under conditions which control or minimize the deactivation by sulphur so as to selectively hydrogenate the more unsaturate portions of the distillate. Hydrofined motor fuels are produced which are extraordinarily responsive to small subsequent additions of antioxidant and antiknock reagents. The lower boiling olefines can be selectively hydrogenated rather than aromatic and higher boiling olefines to yield a motor fuel of improved stability and response to tetraethyl lead additions, particularly with re-.

spect to the lean-mixture octane number.

Another object of the invention is to minimize unnecessary or premature deactivation ofthe fluidized catalytic surfaces by means of a receding temperature gradient,v usually of extra-- g sodium sulphate.

ordinary range, and to responsively maintain this decreasing thermal gradient by adding gaseous hydrogen to the upfiowing reacting vapors, and at the same time compensate decreases of linear vapor velocity due to cooling, while decreasing organic adsorption and increasing the ratio of hydrogenation to desulphurization.

Another object of the invention is to rid the highly spent powder of sulphur and to recover said sulphur, e. g. as sodium sulphate or calcium sulphide. A corollary object is to replace'the prior art practice of roasting the catalytic metal sulphide with means comprising controlled oxidation to catalytic metal sulphate and basic sulphate. Roasting is particularly objectionable in two respects, first the conversion of sulphide to oxide is incomplete, second the oxide is in a grey sintered state respresenting a substantial decrease in the ratio of catalytic to non-catalytic metal.

Another object of the invention is to coact the several steps so as to effect savings of equipment, reactants and heat. For example, water for extraction may be used to recover basic .nickel sulphate fines by simple scrubbing'instead of using expensive electrostatic precipitation and bag filters. Similarly dilute sodium sulphate solution maybe used to recover dry sodium sulphate fines. Sensible heat of the hot spent drying gas is simultaneously recovered. Byproduct carbon dioxide, e. g. from the decomposition of basic nickel carbonate, may be used to carbonate a crude sodium carbonate-hydroxide solution. The hot gases from the sodium sulphate-limestone-coke fusion may be used to spray dry a concentrated impure solutionof Prior art fluid catalysis is generally single stage, the catalyst being diffuse phase. The reaction is highly exothermic with much heat'to be removed; The fluidized catalytic powder 'moves upward concurrently with the reactant vapors at a high constant or rising temperature, usually forming and accumulating carbon. The spent catalytic powder is then reactivated-by fluidized roasting at very high temperatures." My hydrofining is multistage, graded, countercurrent, the catalyst preferably dense phase, the reactionusually only slightly exothermic with relatively little reaction heat to be removed." The fluidized catalyst powder preferably moves downflow at "a relatively low and falling tm'perature. Fluidizing may be obtaind'in'this powder downfiow at a relatively wide range of linear velocities of the fluidized gas} e. g. 5 to 50 centimeters per section, requiring less exacting control. The spent powder withdrawn near the bottom of the hydrofining tower is not usually carbonized. The spent powder may be regenerated by means comprising fluidized oxidation at subroasting temperatures. Carbon dioxide and sulphur dioxide are preferably minor products of such oxidation. My regeneration is a multistep chemical process in which the role of fluidizing is relatively minor.

The hydrofining may be carried out to various extents. A relatively short contact time is suflicient to remove the more labile impurities, such as mercaptans, to render the product sweet, e. g. by the doctor test. A cracked motor fuel distillate is preferably hydrofined incompletely but at least sufficiently to remove labile forms of sulphur. Thus a high sulphur cracked distillate-can be desulphurized to meet the U. S. governmental standard for sulphur, while the olefine content is only partially saturated, and the aromatic content remains essentially unhydrogenated. A larger proportion of the lower boiling than of the higher boiling olefines is preferably hydrogenated. The lower hydrofined fraction may be recycled for further hydrogenation and as a liquid coolant. Minor quantities of gum forming unsaturates which may remain after hydrofining may 'be'removed by other treatments or may be inhibited. Thus the hydrofining may be supple- .mented by other treatments, e. g. a subsequent addition of antioxidant and/or antiknock reagent to the liquid distillate.

My gradient conditions tend to relatively or approximately equalize the extent of hydrofining in each stage, particularly in the non-extreme stages. The catalytic surfaces thereby work at a relatively constant or uniform rate, which minimizes unnecessary deactivation and side reactions. A tendency is noted for one organic molecule to adsorb on each catalytic metal atom. When the ratio of hydrogen to organic vapor is constant I have observed an adsorption decrease as the catalytic surface becomes progressively sulphided and the temperatures progressively raised. When the ratio of hydrogen to organic vapor is decreased as the surface becomes sul- .phided, then the adsorption change is decreased or minimized, particularly with respect to the organic vapor. Herein is a substantial major Q advantage for the countercurrent and stagewise contact of the hydrogen-vapor mixture with a fluid catalytic powder under a gradient of temperature and hydrogen ratios as shown in Fig. 1. As noted in my U. S. Patent 2,174,510, granted October 3, 1939, the range and curvature "of the hydrofining temperature gradient is a function of catalyst activity, y. For fresh catalytic powder of nickel, cobalt, promoted copper, copper, promoted iron, y=1.'7, 1.6, 1.5, 1.4, near unity, are respective exemplary values. The hydrofining range in degrees Kelvin or centigrade is preferably not greater than about 600y'divided by y+3. For the more active catalysts such as nickel, the gradient curvature is S shaped, and some intermediate temperature in the range may be critical, e. g. a temperature near 205 C. For the less active catalysts such as iron, the gradient curvature becomes more nearly linear as the gradient range is shortened. The range of the hydrofining temperature gradient is between C. and 200 C., preferably more than 100 C., particularly with a nickel powder. Fresh nickel catalytic surface rapidly desulphurizes distillate vapors below 150 C.-200 C. Nearly spent catalytic surfaces are -..:desulphurizing up to 300C. when traces of ny drogen sulphide may appear. I prefer to hydrofine sulphur bearing distillates under gradient conditions which prevent liberation of hydrogen sulphide. My hydrofining temperatures are nonpyrolytic, avoiding carbon formation or deposition upon the catalytic powder.

For the metallic component of my catalytic powder I may use one or two or even several of those elements whose precipitated sulphides are black, particularly if they also form black oxide surfaces which are readily reducible in hydrogen to black metal. Such black oxide powders may be somewhator slightly more oxidized than the corresponding sintered non-black oxide of stoichiometric proportion. My preferred group of elements is iron, cobalt, nickel, copper. Iron, nickel, copper are'preferred where catalyst economy is essential, e. g. for motor fuel hydrofining. The preferred hydrogenating or hydrofining element is nickel. Nickel and copper may be used together. A minor proportion of nickel may be added to an iron or copper catalyst. 'Iron, cobalt and nickel are ferromagnetic. Certain magnetic combinations comprising a metallic element such as copper, which is not ferromagnetic, may be used as the hydrofining metal.

Low reduction temperatures, e. g. of a basic carbonate or oxide, constitutes one of several indices to the activity and effective hydrofining range of the catalytic metal. Powder comprising the black oxide is reactive, and is a preferred form of the fresh catalytic metal. The oxide may be mixed with reduced metal or with a readily reducible oxygenated compound of the metal. Thus the basic carbonate may be decomposed by heating to 280 C.-400 C .,.evolving water and carbon dioxide to yield a black oxide. The oxide may be reduced to the metal or a lower oxide concurrently with the hydrofining, particularly when the hydrogenation is substantial. Concurrent hydrogenation and oxide reduction appears to assist the desulphurizing.

The following is a' sample or typical chemical reaction when using dried. and oxidized nickel catalytic surfaces on cracked motor fuel distillates: I

' surfaces can be approximated, e. g. the slow aggregate downflow linear velocity of the catalytic powder is preferably more than 100 fold slower shown in Fig. l.

than that of the upflowing vapor-hydrogen mixture, particularly in the hydrofining reactor as In the above reaction, the mole ratio of hydrogenation to desulphurization is three. 1 This ratio may be varied widely, e. g. increased by usingrelatively more nickel or by 7' means of a higher total pressure, particularly when desulphurizing substantially to completion. Or the ratio of hydrogenation to desulphurization may be decreased, e. g. when using a catalytic powder of lesseractivity'or a lower total pressure. 7

In general, I use. a proportion or ratio of hydrogen in excess of the stoichiometric requirement, preferably at least several fold greater. Values of VHz/VR'in excess of '10 or 20 excessively dilute and retard the hydrofining, where VH2 is the volume of hydrogen gas mixed with the vapor -and Va is the volume of hydrocarbon vapor. Be-

'tween this and -'-the stoichiometric extreme may be noted-twamean values, one a catalytic optiperatures.

= mum of high hydrogen ratio, twoan economic optimum of lower hydrogen ratio. These optima can be approximated or estimated by means of the following equation:

where R is the olefine content of the hydrocarbon vapors, y is the catalyst activity of the powder at any stage. For completely sulphided and spent catalytic surfaces, y approaches 0. For my fresh catalytic nickel surfaces, y-1.7. Since y increases as fresher surfaces are contacted, then the proportion of hydrogen preferably increases in 'the later or cooler stages of a countercurrent contact. N is a coefficient whose value appears to be near 2 or 3 for the catalytic optimum. The proportion of hydrogen for hydrofining may vary substantially from that shown in the approximation above. Thus it may be expedient to add no.

hydrogen in the hottest hydrofining stage, or a proportion less than the economic optimum. Larger proportions or ratios of hydrogen may be used, e. g. cold hydrogen not greatly in excess of the catalytic optimum may be progressively added as fresher catalytic surfaces are contacted in order to decrease the temperatures. The chemical reaction typified in the chemical equation above is exothermic on the order of 80 kilogram calories per gram mol at normal temperatures, but is substantially less at reaction tem- Thus an average near 15 kilogram calories needs be dissipated per gram mol of hydrogen absorbed during hydrofining. It appears drofined, the coolant becoming further hydrofined during recontact. Or a small proportion of liquid water may be mist injected at several or more points or stagesto cool the reacting vapors, particularly in the cooler stages.

drofiningor reaction chamber may contain small cooling pipes, preferably vertical and-parallel to the flow as shown in Fig. 1.

Water under pressure or other liquid coolant is flowed through the inside of these cooling pipes.

- My catalytic powder is fluidized by means of a vapor or vapor-hydrogen mixture at an vupfiowing linear velocity greater than that at which channeling occurs but less than that at which substantial slugging occurs. I prefer a linear gas velocity between 1 or 2 centimeters and 1 or 2 meters per second, e. g. between 1 centimeter and 1 meter for dense or finer powder fluidizing, and greater than 2 or 5 or centimeters but not greatly in excess of 1 meter per second for diffuse phase or coarser powder fluidizing. When changing from low to high sulphur distillates, or from a slow to fast feed of fresh catalytic powder, I prefer to fluidize at increased linear gas velocities. Linear gas velocities herein refer to a velocity calculated with respect to void or free space. A sieve range on the order of 4 or 5 appears to be preferred for improved fluidization.

The hydrofining pressures are between about 1 and 100 atmospheres, preferably betweenabout.

Or a hydistillate, particularly a light petroleum distillate, including motor fuel, naphtha, lighter burning oils, or a pyrolytic or cracked distillate, particularly a light distillate from petroleum, coal, shale, or a light extract or concentrate of the impurities from any of the foregoing. A gas bearing a minor volume of sulphur compounds and carbon monoxide may be hydrofined to convert residual carbon monoxide to methane.-

My invention comprises the following three processes, the first two of which are essential:

1. Fluidized hydrofining under gradient conditions, as exemplified in Fig. l.

2. Regeneration of spent powder, as exemplified in Fig. 2.

3. Recovery of regeneration reagents, exemplified in Fig. 3, preferred when hydrofining motor fuel distillate.

Fig. 1 shows multistage hydrofining under dense phase fluidized conditions. The hydrofining of crude naphtha, particularly motor fuel distillate from petroleum, is used as a preferred example. Liquid naphtha under pressure to inhibit vaporization is pumped down through a bundle of tubes I within hydrofining tower 6, as a liquid coolant for the catalytic powder and gases flowing through tower 6. The, preheated naphtha enters the tubular vaporizing furnace 2 at inlet 3. Naphtha vapor leaves the furnace at exit 4. Extreme heavy ends, polymers andtar are entrained in the centrifugal separator 40., The stripped but crude vapors enter hydrofining tower 6 at the low inlet 5. Hydrogen gas can be introduced with the naphtha vapor at inlet II. The vapors pass upflow through each of seven perforated plates or metal screens I at a linear velocity between 1 or 2 and centimeters per second, thereby fluidizing nearly spent catalytic powder 8. The linear velocity up such a tower need not be constant, e. g. the linear velocity may increase somewhat as the gas mixture moves up the tower. The linear velocity through the perforations or screen may be several fold greater than the velocity immediately below. The perforations or holes are preferably somewhat larger than the coarsest sized powder in hopper '23,, and are sized to allow a small proportion of the catalytic powder to pass downward therethrough.

Spent powder overflows from .5 at outlet 9, and is replaced by less spent catalytic powder entering from downfiow pipe Illa. Five other such pipes, Illb, Inc, IOd, Hie, III), are shown above. Hydrogen, preferably cool hydrogen, may be introduced near the midlevel of each pipe Illa, IOb, Inc, "Id, We, Iflf at inlets IIa, IIb, IIc, IId, He, II Hot hydrogen may be introduced, at inlet II. Each hydrogen inlet is individually controlled 'by a regulator I2, I2a, IZb, I20, I2d, I2e, IZf, preferably automatically, to maintain a temperature near that shown beside each bed. The hydrofined vapor-hydrogen mixture leaves the hydrofining tower at outlet I3, passes to a condenser I4. Cooling water may enter the condenser at inlet I5, leave at outlet IS. The liquid naphtha and excess hydrogen passeslto separator variable speed motor.

a during hydrofining.

' ,hydrofining tubes.

sesame ii. The excess hydrogen :leaves the separator at outlet 18, and is repressured in centrifugal booster or compressor 19, to pass back into the hydroflning tower -15 via :maniiold 20. Make-up hydrogen also enters the system via manifold through regulator 24 onto the topmost and'coolest perforated plate-or screen at inlet 2'5. Temperaturesare relatively constant within each of the seven beds of catalytic powder within the hydrofining tower 6. -Lower boiling fractions or portions of hydrofined-naphtha maybe spray injected into tower 6, e. g. at inlet 26 through regulator 21.

Spent powder overflows at 9 and passes through a oneway pressure reducer 28, e. g. a .lock comprising two plug valves, the plug of each being rotated by means of gears driven by the same One plug is open while the other is closed. The countercurrent steam stripper 29 is shown in vertical-section. Its construction is similar to the hydroflning tower 6. The preferred stripping pressure is one atmosphere. The spent powder passes into stripper 29 at inlet 30, passes downfiow and out at outlet 3|. The water for the stripping steam introduced at inlet 30a may be vaporized by recuperation, e. g. deionized water may be flowed down througha tube bundle (not shown) within .hydroflning tower 6. The spent and stripped powder is pneumatically cooled and conveyed upward through pipe 32 into closed hopper 33. The hopper has an air vent 34 to a recovery bag. The hydrocarbon-steam mixture leaves stripper 29 at outlet 35, the hydrocarbon iscondensed in condenser 36, passing into separator 37. Water is drawn off through the separator bottom38, hy-

. dro'carbon throughthe side outlet 35, any gases through top vent valve 40.

My catalytic powder may be otherwise fluidized For example, the hydrofining canbe carried out in several vertical tubes in series. Thus highly sulphided nickel powder may be fluidized by a vapor velocity greater than 0.1, but not greatly in excess of .1 meter :per second, up the first tube at a temperature of 275-280 C. This vapor may be cyclone separated from spent powder, then mixed with hydrogen, e. g. 0.1 volume H2 per volume of vaporyand fed up the second tube with fresh catalytic .nickel containing powder at a temperature near 233"- 236" C. This vapor-hydrogen mixture may be cyclone separated from the powder, then :mixed with more hydrogen, e. g. (L08 volume Hz :pervolume of vapor, and fed up the second tube with fresher catalytic powder at a temperature near 205-209 C. 'This vapor-hydrogen mixture may be cyclone separated from the powder, then'mixed with more hydrogen, e. g. 0.13 volume H2 per volume of vapor, and fed up the fourth and final tube with freshly regenerated black nickel oxide powder at a temperature near '148-150" C. This vapor-hydrogen mixture may be cyclone separated from the powder. The hydrogen additions here are small, and primarily for the purpose of equalizing linear velocities Substantial cooling may be obtained by intercolers, e. g. water jacketing the vapor lines connecting the four 'Parafiinic or naphthenic vapors such as a lightstraight :run petroleum distillate, may be thus hydrofined withsmall -hydrogen-additions..

:of catalytic .In Fig. :2 .is shown the regenerative conversion metal sulphide to black catalytic metal oxide. My typical -or :preferred catalytic element is nickel. Spent catalytic surfaces downflowing from hopper 33 meet at 4| a flow of hot gas from burner 42 bearingmolecular oxygen to initiate controlled diffuse phase fluidized oxidation of thenickel sulphide inthe oxidation tower 43. Thegas 42 may compriseor consist of natural .gas :or fuel oil burned with a substantial excess of .air. Cold air may :be injected into tower 43 through regulators 44 ,via inlets 45 from .a manifold 46, to maintain the temperatures in tower 43. below the meltingpoint of the catalytic metal sulphide and somewhat below roasting temperatures. Roasting temperatures, e g. on the order of 700 C'., evolve sulphur dioxide and decompose nickel sulphate almost asrapidly as formed to a grey nickel oxide. The powder leaving tower 43 usually consists of a mixturerof nickel sulphate, basic nickel sulphate, together with .a minor proportion of nickel sulphide and nickel oxide. This powder and the gas whirl in cyclone 41. Part of the gas leaving the top of the cyclone can be pumped back to 4!. The remainder or all of the gases contain surfacefines ordinarily requiring expensive equipment to .recover. The gas may be passed through inlet 48 and countercurrently contacted in scrubber 49 let 66 and air venteringinlet 57.

with cold water, preferably deionized water, entering tower 49 at inlet 50. Thereby both heat and nickel compounds are cheaply recovered. The spent gas leaving tower 49 is vented to the atmosphere through exit 5|. Most of the powder through cyclone 41 drops into hopper 52 and is fed through regulator 53 to rotary slurrier 54, where the powder meets the hot scrubbing water from scrubber 49. The slurry passes into thickener 55. Nickel sulphate solution overflows at 56 into tank 51. I The extracted and thickened sludgeleaves the thickener bottom at 58, and is transferred by sludge pump 59 to the open top hopper 60. From thence the sludge is fed-through regulator 6| to the acid resisting rotary slurrier 62 where it meets sulphuric acid or a strong aqueous solution thereof from tank 63 not shown. The acid slurry drops into acid resistant tower 64, packed with carbon or similar acid resisting tower packing 85. The strong acid slurry passing down tower 65 meets steam entering at in- The .air passes upward, agitating the acid slurry, and is vented at tower exit 58. The acid mixture leaves the tower bottom and is pumped by acid resisting pump 69 either to recirculation through tower inlet '19, or as is usual, .into a dilute acid tower ll through inlet 12. Tower H is also packed with acid resisting packing i3 and is vented at outlet 14. .Nickel sulphate solution from tank 51 is pumped through pump 15 into tower H at inlet 16. Dilute acid nickel sulphate solution passes down the tower and is clarified, e. g.

pumped by pump TI through filter pass 58. Any diatonaceous earth is removed in the filter'press l8, and may be recovered. The filtrate flows into tank 19, from whence it is pumped by pump hydrogen ion concentration of the-mixed solution is then adjusted, for examplel at :a ipHxbetween 4;

and 6 to throw down a small precipitate rich in iron and other impurities. This precipitate may be separated, and nickel recovered therefrom. More sodium carbonate solution may be added to the mixed solution, e. g. until the pH is between 9 and 11, and mild agitation continued for a while, e. g. for one hour. The sodium carbonate excess may be minimized if residual nickel (or cobalt or copper) ion is recovered from the filtrate comprising sodium sulphate, e. g. by ion exchange with sodium. As a precipitant, sodium carbonate appears to be catalytically superior to sodium hydroxide, and to be more economically recoverable. Kieselguhr may be added to the slurry in tank 82, preferably during the final precipitation. The valve 84 is then opened, when the slurry is pumped by pump 85 through the filter press 86. The filtered solution is recirculated via line 81 to tank 82 at first, and then when the filtrate is clear, passed through line 88 to tank IOI shown in Fig. 3. When full, the cake in filter press 86 is washed with deionized water from source 89a.., Fi1te r press ,86.is then opened and the wet basic nickel carbonate cake is fed in pieces through kneader 90a if the filter press surfaces have been kieselguhr coated prior to filtration. Whether kneaded or unkneaded, the green wet mixture passes into tunnel drier 90 and onto a moving screen belt at inlet 9|. Dry cake is discharged at outlet 92 into the coarse grinder 93, thence into the fine grinder 94, e g. a continuous conical ball mill with classifier. The basic nickel carbonate powder should be neither extensively uniform nor heterogeneous in size, but rather homologous. basic nickel carbonate is then passed into the blackening vessel 95 at inlet 96. The vessel 95 contains a horizontal helix 96a (motor drive not shown) which moves the powder slowly toward the outlet 91. The green powder is heated to a temperature between about 300 C. and 370 C., e. g. by means of flames directly applied not shown, or by means of a heating fluid such as Dowtherm vapor in a jacket 98. Blacknickel oxide is discharged at outlet 91 into a hopper 99, from which it is pneumatically cooled and conveyed via line I to hopper 23.

In Fi 3 is shown the recovery of regeneration reagents or chemicals, the conversion of an alkaline sodium sulphate solution to a sodium carbonate solution. Dilute and slightly alkaline sodium sulphate solution from tank I 0| passes through pump I 02 and the evaporator I03 at inlet I 04. The evaporator may be multiple effect, not shown, for example two or three effect. Any second effect is heated by steam emerging from the evaporator I03 at exit I05. The concentrated sodium sulphate solution is pumped by pump I06 to the high speed centrifugal sprayer I01 in the top center of spray drier I08, and therein meets a horizontal tangential flow of hot waste gas introduced by pipe I09. The sodium sulphate powder passes out of the spray drier bottom. The recovery of regeneration chemicals may be stopped at this point, using other heating means for the drying, where the hydrofining economicmargin is relatively wide, where the scale of operation is relatively small, or where a market or use for the sodium sulphate is at hand. Otherwise sodium sulphate powder is pneumatically cooled and conveyed to closed hopper III at the tangential inlet H0. Dry sodium sulphate fines in the hot gas leaving the hopper. at outlet H2 pass throughblower I I 20 and intothe countercurrent washing tower I I3 The. powdered.

10 at inlet H4. In tower II3, the flnesplus the sensibile heat of the gas are effectively and inexpensively recovered by means of a small countercurrent stream of dilute sodium sulphate solution entering packed tower H3 at inlet H5. The cool spent gas is vented to the atmosphere at I IS. A hot concentrated solution of sodium sulphate flows through regulator I I! either back into tank IOIorinto1ineII8.

Dry sodium sulphate powder is charged from hopper III through valve H9 into the hopper I20. For each kilo of dry sodium sulphate, a somewhat smaller quantity of crushed limestone is charged from source I23, e. g. 0.8 or 0.9 kilo, together with a still smaller proportion of coke or coal fines from source I24, e. g. 0.4 kilo. Coke fines are preferred; if coal is used, it is preferably of low ash and nitrogen content. The charge from hopper I20 is dropped through furnace inlet I2I into the horizontal furnace I22, shown in vertical section, and lined with flreresisting brick or clay. The inlet I 2| is closed, the furnace I22 is then rotated about a horizontal axis about two revolutions per minute by cog I23, the motor drive of which is not shown.

The flames from the fuel oil or natural gas burner I24 are passed into the furnace at the axial inlet I25, the flames pass in a horizontal direction across the fusing mass I26, leave the furnace at the axial outlet I21, and enter spray drier I08 at the tangential inlet I09. As the charge in furnace I22 fuses, the speed of rotation;

is increased, e. g. doubled or tripled.- When long greenish flames of burning carbon monoxide are emitted from the fused mass as seen through window I28, the reaction is complete, the furnace rotation is stopped, the flames from burner I24 are bypassed (not shown) to I09, the fused black mass is discharged via outlet I29 to insulated tank I30. Meanwhile a new charge of sodium sulphate powder, crushed limestone and coke fines has been placed in hopper I20, and is dropped into the now empty furnace I22, the inlet I2I is closed, the bypass from I24 to I09 is closed, and as before the flames from burner I24 are passed through the furnace and out at I 21, thence again into spray drier I08 at inlet I09.

The fused black mass from tank I30 preferably contains up to 10% free calcium oxide. The fused black mass passes through heated regulator I 3| to the water cooled flaker I32, producing either thin or porous flakes. These black flakes drop onto conveyor I33. and may be temporarily stored in or pass throurzh humid atmosphere I33a to increase flake porosity. From I33 or I33a, the flakes are transported to tray thickener I34 where they are extracted with cold water which warms durin the extraction. The black flakes comprise sodium carbonate and calcium sulphide together with minor proportions of free carbon, sodium hydroxide and calcium carbonate. In the thickener the water dissolves out the sodium carbonate and sodium hydroxide. Crude calcium sulphide sludge leaves the thickener at outlet I 45. The crude alkali solution overflowing at I35 contains a minor proportion of soluble sulphides and thiosulphates which must be removed or oxidized. The overflow solution is pumped by pump I36 to the top of the oxidation tower I 31. The tower may be baflied rather than packed within, e. g. a series ofperipheral baffles I38 slanting downward toward the tower axis, with a superimposed center hori-s zontal baflle I39, somewhat larger than the cam an opening." The downflowing alkali solution meetsan upflowing gas stream entering column The gas contains carbon di'- l'3i at inlet I40. oxide and oxygen and should be free of hydrogen sulphide and mercaptans. .For example, the

gasflfed-into I40 may comprise the gas drawnofi'f at the top of vessel 95-. Nitrogen rich spent gas is vented at MI. The solution sulphides in the alkali solution are converted to sulphates andthiosulphates are oxidized and decomposed carbonate solution leaves filter I43 at outlet I44- and flows into receiving tank- I 45. Samples of the-solution withdrawn at I44- or at valve I46 should be substantially white and tested ortreated free of sulphides before the solution is transferredbypump M! to tank 82.

EXAMPLE 1 Fresh catalytic powder is prepared as shown in Fig. 2 between tank 82 and 99. An equal volume of a-0.25 gram molar warm aqueous solution of pure sodium carbonate is gradually added to a 0.2 molar warm aqueous solution of nickel sulphate. Agitation and heating is then continued for about one or two hours. The green slurry is then filtered througha filter plate coated with diatomaceous earth, the precipitate is then washed 'withdeionized water, avoiding peptization of the precipitate. The precipitate and diatomaceous earth are removed from the press and kneadedtogether, the kneaded green cake is then dried and'pulverized' to a graded size in the inch mesh range 30 to 120 (12 to 48 centimeter mesh). This homologous sized powder is then heated in a slow current of air to a temperature between 320 -3370 C. until black, e. g. as shown in horizontal vessel 95. From hopper 23 this black powder is fed into hydrofining tower 6 near its top at' inlet 25 (Fig. 1) at the rate of about 15 weightsof nickel per 1,000 weights of a petroleum distillate, thermally cracked at relatively high pressure. This motorfuel distillate is derived from California crude, its nitrogen content being unusually large. The liquid distillate to be hydrofined is preheated in tube bundle I, enters furnace 2, leaves at exit 4 as a vapor at a temperature near 300" C., then slightly cools during passage through tar separator 4a, enters hydrofining tower 6 at. inlet at apressurenear atmosphe-res, mixes with 0.4 volume of hydrogen gas entering inlet II, the vapor-Hz mixture upfiows through perforated plate I, fluidizes and reacts with the nearlyspent powder bed at a temperature near'2'75 C. as shown. Additional hydrogen is added as the vapor-hydrogen mixture passes up the tower, e. g; 0.3, 0.2, 0.1, 0.0, 0.2, 1.0, volumes hydrogen per volume hydrocarbon vapor are added at inlets IIa,v II'b, Ilc, IId, He, II respectively. After cooling in condenser I4, hydrofined distillate is drawn off at outlet 22, and the excess'hydrogen isrecycled via booster'I9. The spent'powder consisting mostly of nickel sulphide; leaves the hydrofining tower at outlet 9 and" stripped of hydrocarbons by! steam tower 29*, the steamed" powder is then regenerr. ated by means comprisingremoving the. sulphur; and recovering substantially as calcium sulphide; as shown in Figs. 2 and3. The desulphidecl and regenerated catalytic powder islreused by feeding into the hydrofin-ing tow-er'at inlet 25..

Inspection of'th-e pressure cracked California dis til'late before hydrofining Gravity, A.. P. l.' 5.1: ASTM distillation F:

I; B. P -136, 50% off" 289. 90% ofi" 4.08; E. P. 449." Sulphur distribution in boiling fractions:

In the table-below is a comparison of thegcrudez andhydrofined-product:

i,B QlB. HydIl0: After Hydro.- I finmgfining Sulphur-percent 3 0.09. Color; Waterrwhitm Gum copper dish ;50. Octane numbe 62; Doctor test;; I 5 Negative; silicotungstic tic-latest.-...., d D o..

EXAM, PLE. 2

A nickel catalytic powder is prepared as; described in Example 1'.v Instead of'the1 pure so-- dium carbonate, a. solution containing sodium carbonate plus a. lesser quantityof sodium sulphate is used to precipitate the nickel sulphate solution. The green precipitate of basic nickel carbonate is easier to filter and wash. The so-. dium sulphate of the filtrate can be converted to a mixture of sodium'carbonate and sodium sulphide as shown in Fig. 3, and when purified can bev used to precipitate a new batch of nickel sulphate.

The green nickel basic carbonate precipitate is dried,. sized, heated to blackness, and this powder is fed into hydrofining tower Bat inlet 25 at the rate of aboutB, weights nickel per. 1,000 weights, of, a, petroleum v distillate, thermallycrackedat a temperature of, about 500 C. This motor fuel distillate derived from Venezuela crude is hydrofinedand the powder regenerated as/described in Example 1.

Inspection of cracked Veneeuelzzr,v distillate before I hydrofining Gravity, A. P. I. 52.9

ASTM distillation F.: r

' I. B. P. 'll8 10% 1'74 50% 292 90% 386 E; P1. 415

13 In the table below is a comparison of the crude and hydrofined product:

Before Hydro- After Hydrofining fining Sulphur percent 0.40 0.08. Color Orange Water white. Gum copper dis 590 74. Doctor test Positive r. Negative.

EXAMPLE 3 A catalytic powder prepared as described in Example 2 is fed down at a lower proportion to an upfiowing vapor of a highly cracked petroleum distillate. This distillate is derived from a light solar oil cracked by a minute contact at about 600 C. at 8 atmospheres pressure.

Inspection of cracked distillate before In the table below is a comparison of the crude and hydrofined product:

Before Hydro- After Hydrofining fining Sulphur percent 0.03. Color Water white. Gum copper dish 4 10 I 120. Doctor test Negative.

Tetraethyl lead and an antioxidant such as dibenzyl-para-aminophenol may be added to the hydrofined productfrom Example 2 or 3 to produce a motor fuel without further chemical treatment.

EXAMPLE 4 Fresh catalytic powder is prepared as shown in Fig. 2 between tank 82 and hopper 99. An equal volume of a one-third gram molar warm aqueous solution of sodium carbonate is gradually added to a 0.303 molar warm aqueous solution of mixed sulphates of copper (0.3 molar) and nickel (0.003 molar). Agitation and heating is then continued for about one or two hours. is then filtered through a filter plate coated with diatomaceous earth, the precipitate is then washed with deionized water. The precipitate and diatomaceous earth are removed from the press and kneaded together, the kneaded green cake is then dried and pulverized to a gradedsize in the inch mesh range 40 to 160 (16 to 64 centimeter mesh). This homologous sized powder is then heated in a slow current of hydrogen to a temperature between 300 C. and 400 C. until black. This black powder is fed into hydrofining tower 6 near its top at inlet (Fig. 1).

The liquid coal tar naphtha to be hydrofined is preheated in tube bundle I, enters furnace 2, leaves exit 4 as a vapor at a temperature near 290 C., then slightly cools during 7 passage through tar separator 4a, enters hydrofining tower B at inlet 5 at a pressure near 6 atmospheres, valve I2 is closed so that no hydrogen The green slurryenters inlet II, the vapor upflows through per forated plate 1, fluidiz'es and reacts with thenearly spent powder bed at a temperature near 270 0. Variable volumes of hydrogen are added peratures of the powder bed 8a, 8b, 8c, 8d, 86, 8) are respectively 249, 249, 231, 217 204,

187, 161 C. After cooling in condenser l4, hydrofined naphtha is drawn off at outlet 22 and the excess hydrogen is recycled via booster I 9. The spent powder leaves the hydrofining tower at outlet 9 and is stripped of hydrocarbons by steam in tower 29, the steamed powder is then regenerated by means comprising removing the sulphur and recovering substantially as sodium sulphate or calcium sulphide as shown in Figs. 2 and 3. The desulphided and regenerated catalytic powder is reused by feeding into the hydrofining tower at inlet 25.

In the table below is a comparison of the crude and hydrofined solvent naphtha derived from coal tar:

Evidently almost no alkyl cyclohexane compounds are formed during the hydrofining. When nickel is substituted for the promoted copper catalyst, a few percent of alkyl cyclohexane may be formed. Lower hydrofining pressures may be used with nickel.

The term hydrofining is used generically herein to comprise disulphurization and/or hydrogenation, generally both when sulphur is present. The desulphurizing is generally hydrogenolytic, the hydrogenation usually selective or incomplete, water may be a reaction product. Volatile organic compounds, particularly crude or impure mixtures which rapidly deactivate sulphur sensitive catalytic surfaces during reaction with hydrogen, may be hydrofined substantially as described herein. The following proportion may guide in selecting or estimating a range or gradient of temperatures or a specific temperature within that range. This temperature, K, is in degrees Kelvin.

K 3 K0 is a Kelvin temperature usually higher than the preferred upper limit and characteristic of each reaction. Thus K0 is on the order of600 K. for hydrofining in Examples 1, 2, 3. K0 is on the order of 700 K. for the conversion in Example 5. K0 is on the order of 800 K. for the conversion in Example 6. I prefer to use only the lower and medium values of K, and to discontinue use of the powder before its catalytic activity, 11, reaches zero; particularly in hydrogenations such as described in Examples 5 and 6.

EXAMPLE 5 Naphthalene vapor, particularly when crude or impure, is mixed with hydrogen and selecti-vely consented to. tetrahydronaphthalene with-- r la. vely! minor: forma ion: of ec hy r nap r thale-ne while. fluidi ing. ca alytic nickel p w r.- he p w r ay be p ep r as: escri in xample 1. The naphthalene; v por m y e ydrofined as, described inExample 1., but using several fold greater volumes of hydrogen per volume hydrocarbon vapor. The topmost-one or; two hydrofining stages in hydrofining: tower B may also be omitted. The, unsulphided, nickel 1 Crude methyl and dimethyl naphthalene may be similarly selectively converted to the tetrayd o; pre ue i Nitrobenzene, vapor, particularly when. crude or impure, is mixed with hydrogen and selec-- tively converted to aniline without substantial formation of cyclohexylamine while fluidizing a promoted catalytic iron powder. The catalyst may be prepared as follows:

An aqueous solution comprising iron sulphates. is prepared, e. g. containing ferric sulphate and ferrous sulphate plus lesser proportions of aluminium sulphate, and cupric sulphate. This solution is precipitated with an excess of a highly alkaline compound of sodium, e. g. sodium carbonate solution. The slurry is filtered and washed essentially free of sulphate ion using an alkaline wash water. The alkaline sodium sulphate' solution may or may not be recovered. The alkaline precipitate is dried, and reduced almost to completion in hydrogen.

The nitrobenzene vapor mixed with hydrogen is flowed upward to fluidize the homologous sized and progressively fresher iron powder, preferably with progressive additions of cooling hydrogen up to several fold excess and at progressively lower temperatures. The temperature of the spent or initial contact may be between about 310 and 380 C., the final contact with fresh catalyst is preferably at a lower temperature, e. g., 20-60 C. lower. Most of the unusually large exothermal heat should be dissipated by extra liquid coolant. For example the tube bundle l in Fig. 3 may be extra large or extra. Or liquid water may be spray injected between stages. The spent powder may then be steam stripped, e. g. as shown in tower 29 of Fig. 1. The stripped powder may be oxidized, e. g. with dilute sulphuric acid, the hydrogen collected, washed, purified and used in the reaction. The resultingiron and other sulphates may be precipitated with sodium carbonate solution, the precipitate may be washed, dried, sized and reduced, as described above. This powder may subsequently be used as the fresh catalyst to complete the conversion of nitrobenzene to aniline.

Nitrotoluene may be similarly converted to toluidine, and nitroxylene converted to xylidine. The preferred hydrofining pressure ranges for the conversion by fluid catalytic iron to aniline, toluidine and xylidine is 135, 1-30, 1-25 atmose. pheres, respectively.

Nitrobenzene vapor may be converted to aniline plus minor qualities of cyclohexylamine by means of a fluidized copper catalytic powder prepared as described in Example 4 The hydrofining temperatures are lower than for the: promoted,

iron catalysis, e. g. between the conversion temperatures described in Example 4 and Example 6. The preferred hydrofming pressure ranges for the conversion by fluid catalytic copper to aniline, toluidine and xylidine is 1-25, 1-20, 1-15 atmospheres, respectively.

What I claim is: 1. A method of hydrofining hydrocarbons and substituted hydrocarbons substantially in the vapor phase and which comprises continuously and countercurrently contacting the vapor with used catalytic surfaces ata superatmospheric temperature below that at which substantial pyrolysis occurs with said vapors, the hydroiining pressure being between 1 and 100 atmospheres, said catalytic surfaces comprising an inorganic compound of a metal selected. from the group which consists of iron, cobalt, nickel, and copper, then regenerating the spent catalytic surfaces by means com-prising oxidizing catalytic metal.

sulphide with an oxygen containing gassubstantiallyto the sulphate and chemically reacting thesulpha-tewith aninorganic compound of 'strongalkalinity to form a readily reducible basic compound of thecatalytic metal, heating and reusing these catalytic surfaces in the last hydrofining stage.

2. A method of hydrofining hydrocarbons and substituted hydrocarbons substantially in the vapor phase and which comprises continuously and countercurrently contacting the vapor with used catalytic surfaces at a temperature above 100 C. but below that at which substantial pyrolysis occurs with said vapors, and further contacting the vapor mixed with hydrogen gaswith fresher catalytic surfaces at a temperature not in excess of that in the more spent catalytic surfaces, the hydrofining pressure being between 1 and 100 atmospheres, said catalytic surfaces comprising the inorganic compound of a metal selected from the group. which consists of iron, cobalt, nickel, and copper, then regenerating the spent catalytic surfaces by means comprising oxidizing the sulphide of the catalytic metal substantially to sulphate with an oxygen containing gas, dissolving catalytic metal sulphate in aqueous solution, and chemically reacting said aqueous metal sulphate with a'strong inorganic alkali: to precipitate a readily reducible basic compound of the catalytic metal, and subsequently heating. and reusing the insoluble surfaces as fresh catalytic surfaces in the hydrofming stage.

3. A method of hydrofining hydrocarbons and substituted hydrocarbons substantially in the vapor phase which comprises continuously and countercurrently contacting the vapor with used catalytic surfaces at a temperature below that 0 at which substantial pyrolysis occurs with said vapors, and further contacting the vapor in the presence of hydrogen gas with fresher catalytic surfaces at a temperature not in excess of that in the more spent catalytic surfaces, the hydro- 5 fining pressure being between 1 and 100 atmospheres, said catalytic surfaces comprising the inorganic compound of a metal selected from the group which consists of iron, cobalt, nickeL-and copper, contacting said catalytic surfaces at a 70 linear velocity of the vapor-hydrogen mixture between 0.01 meter per second and the velocity at which substantial slugging occurs, then regenerating the spent' powder by converting the catalytic metal and its compounds substantially 7 to the sulphate by meanscomprising-oxidizing catalytic metal sulphide with an oxygen containing gas substantially to the sulphate, chemically reacting an aqueous solution of the catalytic metal sulphate with a strong inorganic alkali to precipitate a readily reducible basic compound of the catalytic metal, heating and reusing these fresh catalytic surfaces in the last hydrofining stage.

4. A method as described in claim 3 in which the vapors are cooled more than 20 C. but less than 200 C. to a final temperature in excess of about 100 C. during hydrofining by means comprising mixing the vapors with relatively cool hydrogen.

5. A method of hydroflning hydrocarbons and substituted hydrocarbons substantially in the vapor phase and which comprises continuously and countercurrently contacting the vapor with used catalytic surfaces at a temperature below that at which substantial hydrogen sulphide is evolved in the presence of hydrogen gas, and further contacting the vapor in the presence of hydrogen gas with progressively fresher catalytic surfaces at a temperature not in excess of that in the more spent catalytic surfaces, said catalytic surfaces comprising an inorganic compound of a sulphur sensitive catalytic metal selected from the group which consists of iron, cobalt, nickel, and copper, contacting said catalytic surfaces at a linear velocity of the vapor-hydrogen mixture greater than 0.02 but not greatly in excess of 1 meter per second, the hydrofining pressure being between about 1 and 100 atmospheres, then regenerating the spent catalytic surfaces by means comprising oxidizing the sulphide with an oxygen containing gas, dissolving catalytic metal sulphate in aqueous solution, precipitating the metal from said sulphate solution as the basic carbonate by adding an aqueous solution comprising sodium carbonate, then separating and drying and calcining said basic carbonate substantially to a black oxide of the catalytic metal, and reusing said fresh oxidic metal compound in the last hydrofining stage.

6. A method of hydrofining hydrocarbons and substituted hydrocarbons substantially in the vapor phase and which comprises continuously and countercurrently contacting a sulphur and hydrocarbon bearing vapor with used catalytic surfaces at a temperature below that at which substantial hydrogen sulphide is evolved in the presence of hydrogen, and further contacting the vapor with increasing volumes of hydrogen not in excess of about or 20 volumes per volume of vapor and with progressively fresher catalytic surfaces comprising progressively lesser proportions of sulphided to unsulphided metal and also at progressively lower temperatures above about 100 C., said catalytic surfaces comprising an inorganic compound of a catalytic metal selected from the group which consists of iron, cobalt, nickel, and copper, contacting said catalytic surfaces at a linear velocity of the vapor-hydrogen mixture greater than 0.01 but not greatly in excess of 1 meter per second, the hydrofining pressure being between 1 and 100 atmospheres, and subsequently removing essentially all the sulphur from the most sulphided catalytic surfaces by means comprising oxidizing the catalytic metal sulphide with an oxygen containing gas substantially to the sulphate, dissolving catalytic metal sulphate in water, precipitating from said sulphate solution a readily reducible inorganic basic compound of the catalytic metal by adding an aqueous and strongly alkaline compound of 18 sodium, and reusing the desulphided catalytic surfaces in the final and coolest hydrofining contact.

7. A method of hydrofining hydrocarbons and substituted hydrocarbons substantially in the vapor phase and which comprises continuously and countercurrently contacting the vapor with used catalytic powder at a superatmospheric temperature below that at which substantial hydrogen sulphide is evolved in the presence of hydrogen gas, and further contacting the Vapor with fresher catalytic powder at lower temperatures above about C., the cooling being more than 20 C. but less than 200 C. and obtained by means comprising mixing the vapor with relatively cool hydrogen, said powder comprising the inorganic compound of a catalytic metal selected from the group which consists of iron, cobalt, nickel, and copper, contacting said catalytic surfaces during hydrofining at a linear velocity of the vapor-hydrogen mixture greater than 0.02 but not greatly in excess of 1 meter per second, the hydrofining pressure 'being between about 1 and 100 atmospheres, then regenerating the spent powder by converting the catalytic metal and its compounds substantially to the sulphate by means comprising oxidizing catalytic metal sulphide with an oxygen containing gas, precipitating the catalytic metal from its sulphate solution as the basic carbonate by adding an aqueous solution comprising sodium carbonate, then separating and heating said basic carbonate to a black powder comprising the oxide of the catalytic metal, reusing said fresh powder in the last hydrofining stage, and evaporating the sodium sulphate solution remaining after removal of the basic carbonate precipitate to recover sodium sulphate.

8. A method of hydrofining hydrocarbons and substituted hydrocarbons substantially in the vapor phase and which comprises continuously and countercurrently contacting motor fuel distillate vapor with a fluidized sulphur sensitive catalytic powder comprising an inorganic compound of a catalytic metal selected from the group which consists of iron, cobalt, nickel, and

copper, then further contacting the vapor mixed with hydrogen gas with fresher catalytic powder at a temperature not in excess of that in the' more spent catalytic surfaces, the hydrofining temperatures being above about 100 C. but below the temperature at which substantial pyrolysis occurs with said vapors, fiuidizing said powders by contact with the vapor-hydrogen mixture upflowing at a linear vapor velocity greater than 0.02 but not greatly in excess of 1 meter per second, the hydrofining pressure being between about 1 and 100 atmospheres, then regenerating the spent powder by means comprising heating said powder in a gas containing oxygen to a temperature less than the roasting temperature to substantially but incompletely oxidize the metal component without substantial evolution of sulphur dioxide, substantially dissolving incompletely oxidizing metallic surface with sulphuric acid, adding an alkaline excess of an aqueous solution comprising sodium carbonate to the aqueous solution comprising the sulphate of the catalytic metal to precipitate the basic carbonate of said metal, separating said basic carbonate roasting the basic carbonate to drive off most of the water and carbon dioxide, and subsequently reusing this powder as the fresh catalytic surfaces.

9. A method of hydrofining hydrocarbons and substituted hydrocarbons substantially in the 19 vapor base and which comprises continuously and countercurrently contacting a sulphur and hydrocarbon bearing vapor with a fluidized catalytic powder comprising both sulphided and unsulphided nickel at a temperature somewhat below that at which substantial hydrogen sulphide is evolved in the presence of hydrogen, further contacting the vapor together with an excess of hydrogen gas with powder comprising lower proportions of sulphided to unsulphided nickel and at temperatures above about 100 C. but not in excess of that in the more spent catalytic surfaces, fluidizing said powders by contact with the vapor-hydrogen mixture upflowing at a linear vapor velocity greater than 0.02 but not greatly in excess of 1 meter per second, the hydrofining pressure being between about 1 and 30 atmospheres, then converting the highly sulphided nickel powder to nickel sulphate by means comprising heating said powder in a gas containing oxygen to an incipient roasting temperature below about 700 C. so that only a minor proportion of the nickel sulphide is converted to nickel oxide and sulphur dioxide, precipitating the nickel sulphate aqueous solution with an aqueous solution comprising sodium carbonate, separating and heating the nickelous precipitate to drive off water and carbon dioxide, reusing said powder as the fresh catalytic surfaces, recovering and dehydrating the solution comprising sodium sulphate.

10. A method of hydrofining hydrocarbons and substituted hydrocarbons substantially in the vapor phase and organic vapors which comprises continuously and countercurrently contacting a sulphur bearing hydrocarbon vapor with catalytic surfaces comprising both nickel sulphide and nickel at a temperature between about 220 C. and 300 C., further contacting the vapor together with an excess of hydrogen gas with fresher catalytic surfaces containing relatively less nickel sulphide and at a hydrofining temperature above about 100 C. but not in excess of that in the more spent catalytic surfaces, contacting said nickel comprising surfaces with the vapors being hydrofined at a linear vapor velocity greater than 0.02 but not greatly in excess of 1 meter per second, the hydrofirn'ng pressure being between about 1 and 30 atmospheres, then converting the most sulphided nickel surfaces to nickel sulphate by means comprising heating the spent catalytic surfaces in a gas containing oxygen to an incipient roasting temperature below about 700 C. so that only a minor proportion of the nickel sulphide is converted to nickel oxide and sulphur dioxide, oxidizing nickel oxide to nickel sulphate by a reagent comprising sulphuric acid, precipitating the nickel sulphate aqueous solution with an aqueous solution comprising sodium carbonate, separating the green nickelous precipitate,

roasting said precipitate to blackness, using said decomposed surfaces as the fresh catalytic surfaces, recovering and dehydrating the solution comprising sodium sulphate, incompletely reacting this dried salt by fusing with a crushed lime- I stone and a lesser mass of free carbon to form a black mass consisting substantially of sodium carbonate and calcium sulphide, extracting an impure sodium carbonate from the black masswith water, oxidizing the sulphides in said alkaline 20 solution substantially to sulphates by contacting with a gas comprising oxygen and adding the sodium carbonate solution essentially free of sulphides to the nickel sulphate to precipitate basic nickelous carbonate.

11. A method of hydrofining which comprises continuously and countercurrently contacting the vapor of a light hydrocarbon distillate with a fluidized powder comprising nickel sulphide and nickel at a temperature between about 220 C. and 300 C., and further contacting the vapor with progressively fresher powder comprising a lesser proportion of sulphided to unsulphided nickel and at progressively lower temperatures but in excess of about 100 (3., the cooling being obtained by means comprising both a liquid cool.- ant and mixing the vapor with relatively cool hydrogen, fiuidizing said catalytic powder in the dense phase by upflowing the vapor-hydrogen mixture therethrough at a linear velocity between 0.01 and 1 meter per second, the hydrofining pressure being between about 1 and 30 atmospheres, then converting the incompletely sul phided nickel surfaces to nickel sulphate by means comprising heating the spent powder in a gas containing oxygen to an incipient roasting temperature below about 700." C. so that only a minor proportion of the nickel sulphide is converted to nickel oxide and sulphur dioxide, oxidizing said. nickel oxide to nickel sulphate by a reagent comprising sulphuric acid, precipitating the nickel sulphate aqueous solution with an aqueous solution of sodium carbonate and also containing a lesser proportion of sodium sulphate, separating and converting the, green nickelous precipitate to a finely divided solid comprising black nickel oxide, reusing said powder as the fresh catalytic surfaces at a hydrofining temperature not greatly in excess of 100 0., recovering the sodium sulphate solution and subsequently dehydrating to recover sodium sulphate powder, fusing said powder with a nearly equal mass of crushed limestone and a lesser mass of free carbon to form to a black mass consisting substantially of sodium carbonate and calcium sulphide, extracting an impure sodium carbonate from the black mass with water, desulphiding said alkaline solution, and adding the sodium carbonate solution essentially free of sulphides to the nickel sulphate solution to precipitate basic nickelous carbonate.

12. A method as described in claim 11 in which the crude vapor consists of a cracked motor fuel distillate derived from petroleum.

MARION H. GWYNN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,073,578 Gwynn Mar. 9, 1937 2,174,510 Gwynn Oct. 3, 1939 2,273,297 Szayna Feb. 17, 1942 2,273,299 Szayna Feb. 17, 1942 2,332,572 Hepp et al. Oct. 26, 1943 2,337,358 Szayna Dec. 21, 1943 2,367,281 Johnson Jan. 18, 1M5 2,444,990 Hemminger July 13, 1948 

1. A METHOD OF HYDROFINING HYDROCARBONS AND SUBSTITUTED HYDROCARBONS SUBSTANTIALLY IN THE VAPOR PHASE AND WHICH COMPRISES CONTINUOUSLY AND COUNTERCURRENTLY CONTACTING THE VAPOR WITH USED CATALYTIC SURFACES AT A SUPERATMOSPHERIC TEMPERATURE BELOW THAT AT WHICH SUBSTANTIAL PYROLYSIS OCCURS WITH SAID VAPORS, THE HYDROFINING PRESSURE BEING BETWEEN 1 AND 100 ATMOSPHERES, SAID CATALYTIC SURFACES COMPRISING AN INORGANIC COMPOUND OF A METAL SELECTED FROM THE GROUP WHICH CONSISTS OF IRON, COBALT, NICKEL, AND COPPER, 